Backtesting Arena

Get Funding Rate Snapshot

arena_get_funding_rate

Read-only

Are longs or shorts paying right now? Latest BTC perpetual funding rate, averaged across up to 4 exchanges (Binance, Bybit, OKX, Deribit; 8h settlement cadence). Returns the day's averaged value plus each exchange's own value (no moving average or Z-score — for the history use arena_get_funding_rate_history via arena_call_extended). Positive = longs pay shorts (bullish bias), negative = shorts pay longs (bearish bias). Read coverage before comparing values across dates: it says how many exchanges stand behind that day (4 = full average, 1 = a single exchange), and a day-over-day move can be a change in composition rather than in the market; venues_present/venues_missing name the exchanges. provenance grades the average (full = all exchanges, partial, thin = under half — never a basis for a verdict); fields="full" adds the venue spread in bps and the min/max interval of the venue values. A value of exactly 0.0001 (0.01 % per 8h) on many days is the exchanges' base-rate clamp on USDT perpetuals, not a cap in our pipeline: it means "no premium beyond the base rate", and values above it are real market readings. [Free tier]

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "arena_get_funding_rate"
  }
}

Input Schema

Name	Required	Description	Default
`fields`	No	Omit for the default response, which carries `provenance` in short form (grade full/partial/thin, sources_used, sources_expected). 'full' adds the long form: sources_missing (named), sources (licence attribution names), grade_reason, as_of — plus per-part provenance where the composite has parts. A `thin` grade (under half the expected inputs) is never a basis for a verdict or a ranking.

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedOct 29, 2026
- removedInput schema / additionalProperties
```
Removed value: -false
```

Changed3 schema fields changedOct 13, 2026

addedInput schema / $schema

Added value: +"http://json-schema.org/draft-07/schema#"

addedInput schema / additionalProperties
```
Added value: +false
```

addedInput schema / properties / fields

Added value: +{
+  "description": "Omit for the default response, which carries `provenance` in short form (grade full/partial/thin, sources_used, sources_expected). 'full' adds the long form: sources_missing (named), sources (licence attribution names), grade_reason, as_of — plus per-part provenance where the composite has parts. A `thin` grade (under half the expected inputs) is never a basis for a verdict or a ranking.",
+  "enum": [
+    "full"
+  ],
+  "type": "string"
+}

Changed2 schema fields changedAug 25, 2026

removedInput schema / properties / context

Removed value: -{
-  "description": "Explain why you are calling this tool and how it fits into the user's overall goal. This parameter is used for analytics and user intent tracking. YOU MUST provide 15-25 words (count carefully). NEVER use first person ('I', 'we', 'you') - maintain third-person perspective. NEVER include sensitive information such as credentials, passwords, or personal data. Example (20 words): \"Searching across the organization's repositories to find all open issues related to performance complaints and latency issues for team prioritization.\"",
-  "type": "string"
-}

removedInput schema / required
```
Removed value: -[
-  "context"
-]
```

First observedJul 13, 2026

TDQS

A4.6/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations only declare readOnlyHint=true, so the description carries the real burden and does it well: it discloses the 8h settlement cadence, the averaging composition, that no moving average or Z-score is applied, how `coverage` changes comparability across dates, what `provenance` grades mean, and the base-rate clamp at 0.0001. It also warns that a day-over-day move may reflect composition change rather than market movement — genuinely non-obvious behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

It front-loads the core question and headline reading ('Positive = longs pay shorts'), then layers caveats. The single dense paragraph is information-rich but tightly packed — the coverage/provenance/clamp caveats could be broken into shorter units for faster scanning, though essentially every clause carries decision-relevant content.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

This is a one-parameter read tool with no output schema, so the description must explain return semantics — and it does: averaged value plus per-exchange values, coverage and venue lists, provenance grading, and the optional spread fields. An agent has everything needed to call it and to interpret the result without guessing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and the enum is documented, so baseline is 3; the description goes beyond it by stating that fields="full" adds the venue spread in bps and the min/max interval of venue values, which the schema's own enum description does not mention. That is concrete added meaning about what the flag actually changes.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The very first line names the specific resource and scope: latest BTC perpetual funding rate averaged across up to 4 named exchanges. It also explicitly distinguishes itself from the history variant, so an agent can separate this snapshot tool from arena_get_funding_rate_history without opening either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It names an alternative ('for the history use arena_get_funding_rate_history via arena_call_extended') and gives a conditional usage rule ('Read `coverage` before comparing values across dates'). What's missing is any explicit exclusion for when this snapshot should not be used, and the named history tool is only reachable through arena_call_extended rather than being a direct sibling, which adds a hop the agent must infer.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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